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Instruction for Use | HCA 56x and 8x8
designs lead to different measuring conditions for the temperature sensor installed to the
radiator.
K : Rating factor total
KQ : Rating factor for the standard performance of the radiator, stated in KW. This value is
calculated with the data received by taking measurements and the manufacturer’s
data.
KC: Rating of the C-value of the radiator temperature sensor. For each type of radiator this
value is measured on the test rig. The respective KC-value can be taken from the table
with the rating factors.
KT: Rating of the design ambient temperature. Normally KT = 1.
10.2 Table of Rating Factors
A detailed summary of Kc values in Excel / PDF format is available upon request.
10.3 Rating Factor according EN 834:2013
Except
Rating factor (EN 834:2013 Chapter 3.36) :
With the following rating factors the display values of each heat cost allocator can be con-
verted into consumption values which are suitable to be used for billing the heating costs
according to consumption.
Rating factor KQ for the heat output of the radiator (EN 834:2013 Chapter 3.37 and 5.3.1) :
The rating factor KQ is the (non-dimensional) numerical value of the standard performance of
the radiator stated in watts or kilowatts.
The thermal output of a radiator in a thermally stable test booth at flow, return and air tem-
peratures of 90 °C, 70 °C and 20 °C, the air temperature being measured at a height of 0,75 m
above the floor and a distance of 1,5 m in front of the heating surface, is the reference output
relevant for the rating factor KQ (reference system Q(60 K)).
Rating factor Kc for the thermal coupling of the sensors (EN 834:2013 Chapitre 3.38 and 5.3.2)
The rating factor Kc takes into account the different thermal couplings to the temperature
sensors and the different designs of the effective heating surfaces.
Kc is calculated as the quotient of the basic counting rate RB and the counting rate RE at the
temperatures of the sensors on the radiator to be rated operated at base condition:
Rating factor KT for rooms with low design ambient temperatures which deviate from the basic
reference air temperature (EN 834:2013 Chapter 3.39)
For heat cost allocators with the single sensor measuring system, the rating factor KT takes
into account the change in performance and the change in temperature of the sensors at
design ambient temperatures which are lower than the reference temperature.
Resulting Rating Factor K (EN 834:2013 Chapter 5.3.3)
The overall rating factor K is received by multiplying the individual rating factors:
K = KQ x KC x KT
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